tbuckley/cabot-search huggingface dataset:
P02.12.B UNDERSTANDING THE ROLES OF EPHRIN A5 IN GLIOBLASTOMA AND ITS POTENTIAL AS A THERAPEUTIC TARGET
Authors: N Skarne, R D'Souza, L Harris, U Baumgartner, C Offenhauser, S Akgül, K Beckett, A Boyd, B Day
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastoma (GBM) is the most common and aggressive malignant primary brain cancer and is associated with very poor patient outcomes. GBM has been classified into three cell subtypes (proneural (PN), classical (CL), and mesenchymal (MES)), which have been further defined into four plastic cell states (neural-progenitor-like (NPC-like), oligodendrocyte-progenitor-like (OPC-like), astrocyte-like (AC-like), and mesenchymal-like (MES-like)). Existing treatment options have had limited success in improving overall survival, with the extreme heterogeneity present in GBM presenting a major barrier to effective therapy. Thus, there is an urgent need to develop more effective therapeutic strategies which better capture heterogeneity and delay tumour relapse. Several erythropoietin-producing human hepatocellular (Eph) receptors and ephrin ligands have been shown to be functionally overexpressed in cancer and have become attractive therapeutic targets. EphA3 has previously been shown to be a functional, tumour-specific target, frequently elevated in the MES subtype. We identified ephrin A5, the high-affinity ligand of EphA3, to be frequently co-expressed with EphA3 in GBM tumours. However, unlike EphA3, the mechanisms of ephrin A5 in GBM remain understudied. We therefore believe that ephrin A5 serves as an attractive synergistic target for the treatment of GBM. MATERIAL AND METHODS We examined the expression of ephrin A5 in a panel of GBM patient specimens. A panel of GBM tumours were also selected for immunohistochemical and spatial transcriptomics analysis. For in vitro functional studies, ephrin A5 was overexpressed in several GBM primary cell lines. Assays examining proliferation, stemness and differentiation were performed. RESULTS Expression of ephrin A5 was comparable to EphA3 in GBM. 64% of GBM tumours analysed showed higher levels of ephrin A5, relative to the highest normal brain specimen. Initial immunohistochemistry analysis suggests EphA3 and ephrin A5 to be expressed discretely on over 75% of the total tumour mass. Spatial transcriptomics analysis suggests ephrin A5 to be enriched in cells of the AC-like cell state. In vitro overexpression of ephrin A5 was shown to reduce neurosphere formation and induce differentiation of GBM cells. CONCLUSION EphA3 and ephrin A5 are overexpressed in a portion of GBM tumours. Critically, there was a strong mutually exclusive expression to different compartments of the GBM tumour, covering the vast majority of the total tumour mass. Our data suggests that ephrin A5 overexpression drives a less aggressive, more differentiated AC-like tumour phenotype. Thus, dual targeting of EphA3 and ephrin A5 in GBM could provide an opportunity to better capture tumour heterogeneity and achieve more durable therapeutic responses.
P08.01.A FAMILY SUPPORT NEEDS IN GLIOBLASTOMA - FROM RELATIVES’ PERSPECTIVES
Authors: P Ståhl, I Henoch, A Smits, B Rydenhag, A Ozanne
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastoma is the most common and aggressive brain tumour in adults. In spite of standard treatment by surgery followed by radiation and chemotherapy, the average life expectancy is only 10-15 months. As such, glioblastoma affects the family situation and relatives around the patient need support. There is a lack of knowledge about their experiences of support during the illness. The aim of this study was to investigate support needs during the illness trajectory in glioblastoma from the relatives’ perspectives. MATERIAL AND METHODS In this study, 12 relatives (7 partners, 3 children, 1 sister, 1 friend) to patients with a histologically-confirmed diagnosis of IDH-wt glioblastoma since at least 2 months and age ≥ 18 years at the time of diagnosis, were interviewed individually based on a semi-structured interview guide. Interviews took place on one occasion by physical or digital meeting or via telephone, based on the participant's preferences. The interviews were audio recorded and transcribed verbatim. Data collection occurred from March 2022 until December 2022. The analysis using inductive qualitative content analysis is in progress. RESULTS Preliminary results show that relatives were mostly satisfied with the support from the health care. However, they lived in a very stressful situation and parts of the support could be better organized. It was important for them with clear and correct information regardless of the outcome. The waiting time before and after MRI, living in limbo with anxiety of what would be found, was particularly stressful and they desired processing with faster answers. Availability to the health care was an important factor and because of the difficult situation they preferred digital meetings instead of physical meetings. Further, they found it difficult to manage the contacts with different health care instances and thought it would be helpful with support to navigate them to correct instance. CONCLUSION The preliminary results indicate that support to the families should be more structured och focused on clearness, high availability and openness for the family’s needs, and guidance in the health care system.
P12.06.A PERICYTE-LIKE CELLS EXPRESSING FIBROBLAST ACTIVATION PROTEIN ARE MAIN PRODUCERS OF FIBRILLAR EXTRACELLULAR MATRIX IN GLIOBLASTOMA
Authors: P Vymola, E Garcia-Borja, J Cervenka, E Balaziova, B Vymolova, P Vodicka, P Busek, A Sedo
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Compared to the normal brain, glioblastomas (GBMs) contain higher amounts of extracellular matrix (ECM) composed of fibrillar proteins such as collagen I and fibronectin. These proteins are associated with glioma cell invasion and poor clinical outcome of GBM patients, but their origin remains unclear. The highest levels of fibrillar ECM can be found in perivascular niches, which are, among others, resided by fibroblast activation protein (FAP) expressing pericyte-like cells. The aim of this study was to determine the role of FAP+ pericyte-like cells in the production of fibrillar ECM proteins and their importance in glioma cell biology. MATERIAL AND METHODS FAP+ pericyte-like cells, glioma stem-like cells (GSCs) and primary endothelial cells were isolated from human GBMs. M2 macrophages were differentiated from monocytes isolated from healthy donors´ buffy coats. The expression of FAP, collagen I and fibronectin in GBM tissues and different cell types (FAP+ pericyte-like cells, glioma cell lines, GSCs, M2 macrophages) was analyzed by immunohistochemistry and ELISA. FAP+ pericyte-like cells and glioma cells were used to prepare extracellular matrices, which were analyzed using mass spectrometry. Solubilized ECM was used in a modified transwell migration assay. RESULTS Compared to the non-tumorous brain, high levels of collagen I and fibronectin were present in the vicinity of FAP+ pericyte-like cells in GBMs. The expression of collagen I and fibronectin was higher in GBMs with higher FAP expression. In vitro, FAP+ pericyte-like cells produced the largest amount of collagen I and fibronectin compared to other cell types and secreted these proteins extracellularly, resulting in production of 3D extracellular matrices rich in collagen I and fibronectin. Mass spectrometry revealed that the ECM produced by FAP+ pericyte-like cells strongly differs in composition compared to glioma cell ECM. The ECM produced by FAP+ pericyte-like cells enhanced migration of glioma stem-like cells. CONCLUSION FAP+ pericyte-like cells are the main producers of fibrillar ECM proteins such as collagen I and fibronectin in GBM tissue. By this means, their presence within the GBM microenvironment affect the migration of glioma stem-like cells. Funding: Supported by the National institute for cancer research (LX22NPO5102), Charles University Grant Agency (GAUK 1084120) and Centre for Tumour Ecology (CZ.02.1.01/0.0/0.0/16_019/0000785). EATRIS-CZ (LM2023053), Cooperatio Program, research area ,,Oncology and Haematology", and Ministry of Health of the Czech Republic (NV19 03 00501).
P11.42.A LONG- AND SHORTIME SURVIVORS WITH GLIOBLASTOMA IDENTIFIED BY FLT PET/MR AND METABOLOMICS
Authors: M Sandström, S Larhed, J Axelsson, B Björblom, T Asklund
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Patients with glioblastoma still have a dismal prognosis despite multimodal treatment with surgery and radiochemotherapy. Sometimes these patients also suffer from difficulties in the interpretation of outcome from treatment. Since most patients affected by glioblastoma have a short survival it is of outermost importance that ineffective treatment is discontinued in time to spare them from unwanted side effects. MATERIAL AND METHODS 48 patients with suspected glioblastoma were included in a clinical study at Umeå University Hospital between the years 2015-2019. Patients were treated according to clinical routines with surgery and radiochemotherapy and within the framework of the study they performed up to four 18F-flourothymidine (FLT) PET/MR and serial blood-tests for metabolomics. Blood samples were analyzed at Metabolon, USA and the metabolomic pattern were compared with clinical and radiomic data. RESULTS The measures of standardized uptake values (SUV) and tumor volumes show a higher SUV for short-time survivals compared to long-time survivors but only a significant difference for the MR-measures Vtumor, Vtotal after 6 weeks of treatment. Regarding blood samples the metabolite patterns could separate patients living long (&amp;gt;3 years) and patients living short (&amp;lt;500 days) in blood samples taken both preoperatively and after six weeks of radiochemotherapy. CONCLUSION New methods are needed to accurate assess prognosis and outcome of treatment for patients with glioblastoma. This clinical study gives new insights in foreseeing prognosis for patients with glioblastoma by using 18F-flourothymidine (FLT) PET/MR and also by serial blood sampling during treatment. Both results of FLT PET/MR and the impact of metabolomics will be presented and discussed at the conference.
JS07.5.A PROGNOSTIC FACTORS ASSOCIATED WITH POOR OUTCOME IN ADULT PATIENTS WITH MEDULLOBLASTOMA
Authors: Y J GARCILAZO-REYES, P Dal-Col, F Bielle, K Mokhtari, L Feuvret, J Jacob, A Duran-Pena, L Capelle, J Savatovsky, F Bourdeaut, J Masliah-Planchon, B Cacho-Díaz, K Hoang-Xuan, A Idbaih, F Laigle-Donadey
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Medulloblastoma (MB) is a rare tumor in adults. Current recommendations are based on scarce data available in adults, and mostly derived from pediatric series. Prognostic factors have not been uniformly defined in adults to date. MATERIAL AND METHODS We retrospectively collected all cases of adult patients diagnosed and treated between 1995 and 2019 in our institution for histopathological proven MB. We described patient´s characteristics, disease features, treatment modalities and studied the prognostic factors for survival outcomes using univariate and multivariate analysis. RESULTS We identified a total of 89 cases. Male gender (66%), lateral cerebellar location (48%), desmoplastic/nodular histology (43%), Sonic Hedgehog molecular group (76%) and Chang´s M0 (72%) were the most frequent patient´s and disease characteristics. Patients mostly achieved complete resection/near total resection (62%); surgery followed by chemotherapy/radiotherapy (CT/RT) was the most frequent initial strategy (76%), favoring carboplatin-based regimens (70%), posterior fossa RT ≥50 Gy (71%) and craniospinal RT ≥ 30 Gy (59%) as the most frequently regimen used. According to the Association of French Speaking Neuro-oncologists and the European Reference Network on Rare Adult Cancers risk scales (ANOCEF and EURACAN), we found 44 and 48% of intermediate-risk patients and 49 and 45% of high-risk patients, respectively. Both cerebral and spinal presentation at diagnosis was documented in 16 (18%) patients. Complete response was achieved in 71(80%) patients. Nine was the maximal number of progressions documented, 35(39%) patients relapsed, CT was the preferred strategy at relapses, privileging carboplatin-based regimens at first relapse. The median overall survival (mOS) was 124.42 months (95%CI 68.53 - 180.11) and the median progression free survival (mPFS) was 30.48 months (95%CI 13.46 - 47.51), the 5-year OS was 53% and the 5-year PFS was 51%. In multivariate analysis, Chang´s ≥ M2 metastatic classification (p=0.001), no CT in association to RT (p=0.005), and lower doses on craniospinal RT &amp;lt;30 Gy (p=0.015) were associated with poor prognosis for OS; Chang´s ≥ M2 (p=0.009) was also a prognostic factor for poor PFS. CONCLUSION This study dedicated specifically to adult MB patients suggests relevant prognostic factors for adult MB patients. We identify Chang´s ≥ M2 as poor prognostic factor of OS and PFS, and we confirm that the use of CT/RT at diagnosis and RT doses ≥ 30 Gy are associated with better survival in adults MB.
P11.30.A LONG-TERM SURVIVING GLIOBLASTOMA. CLINICAL, MOLECULAR AND SURVIVAL ANALYSES
Authors: S Comas Antón, S Moreno, M Antelo, C Carrato, C Balaña, S Castañer, A Hernández, C Hostalot, M Domenech, S Villà
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastoma (GB) has a poor prognosis with median overall survival of 12-14 months. According to literature, patients surviving more than two years has progressively increased since 2005 and represent approximately 18% of this population, being considered long-term survivors (LTS). The aim of this study is to retrospectively analyze GB LTS treated in our Neurooncology Unit. MATERIAL AND METHODS From December 2009 to March 2021, 49 GB LTS patients were identified in our oncology data base, representing 21,7% of GB patients electronically registered during the same period. Patients were diagnosed and treated for GB according to the current WHO CNS classification at the time of diagnosis. Clinical and molecular characteristics as well as treatment and survival data were analyzed. Classic prognostic factors were analyzed including contact with the subventricular zone (SVZ) which has been identified as prognostic factor in some previous studies. RESULTS Median age at diagnosis was 57 years (range: 30-75 years). Median overall survival (OS) and median time to first progression were 43.6 months and 20.7 months respectively, with 9 patients alive and 6 patients without recurrence at the time of analyses. Rate of patients surviving more than 3, 4, 5 and 7 years were 55,1%, 20,4%, 12,24% and 6,12% respectively. Patients received a median of 2 rescue treatments after first relapse (range: 0-6 lines), including systemic therapies, surgery and re-irradiation. Rates for gross total resection, subtotal resection and biopsy were 32,6%, 47% and 20,4% respectively. pMGMT methylated patients and lesions without SVZ contact rates were 73,5% and 42,8% respectively. IDH analyses was available for 61.22% of our GB LTS patients (90% were IDH wild type and 10% mutant IDH, which according to WHO CNS 2021 classification would actually be defined as Astrocytoma grade 4). No statistical differences for OS or time to first progression were found according to sex, age (&amp;lt;55 years versus ≥55 years), pMGMT methylation status; Karnofsky performance status (≤70% versus &amp;gt;70%) and contact or not with the SVZ. CONCLUSION Classical prognostic factors did not show statistical differences for OS and time to first recurrence in our GB LTS sample, which could be explained by the small number of patients in the sample and the absence of statistically comparable differentiated groups for some of the variables. Larger and prospective analyses of GB LTS are needed. Molecular analyses with next generation sequencing (NGS) technics and radiomics analyses could apport new information predicting GB LTS.
P14.04.B CIRCULATING TUMOR CELLS AS A NON-INVASIVE GLIOBLASTOMA DIAGNOSTIC AND PROGNOSTIC TOOL
Authors: F Lessi, M Morelli, S Franceschi, P Aretini, G Ferri, M Menicagli, F Pasqualetti, C Gambacciani, F Pieri, G Grimod, A Di Stefano, O S Santonocito, C M Mazzanti
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Circulating tumor cells (CTCs) detection in the blood of glioblastoma (GBM) patients can facilitate the assessment of tumoral information without the need for invasive approaches. Our aim is to use GBM CTCs to obtain knowledge about the tumor and improve the current GBM diagnosis and prognosis. MATERIAL AND METHODS We collected primary, matched recurrent GBM and healthy controls blood samples. CTCs were enriched from whole blood controls with Parsortix Cell Separation System and analysed on DEPArray system. CTCs were recognized by immunofluorescence with GFAP.The CTCs have been counted for all the samples. Copy Number Aberrations (CNAs) analysis was performed on CTCs. To compare CTCs genetic background with the same patient’s primary and recurrence tissues, whole exome sequencing (WES) was realized on tumor tissues. Recurrence of GBM was diagnosed according to the RANO criteria +/-path proven second surgery +/- FET PET imaging proven. We assessed tumor volume of contrast enhanced (CE) (as a surrogate marker of BBB damage) and nCE at the time of the CTCs collection by seminautomatic segmentation on ITKsnap software. RESULTS We found CTCs in GBM patients newly diagnosed at the time of first surgery (86%) but also at recurrence (100 %). Cell counting demonstrated in both primary and recurrent GBM patients’ blood a statistically significantly higher number of CTCs compared to healthy controls (average of cells number 15.8 vs 2.3). Interestingly, recurrent GBM patients showed more CTCs than primary GBM patients (average 9 vs 22.7). CNAs analysis confirmed the tumor status of the selected CTCs. Some of GBM classical mutations (in HTERT promoter, BRAF, PTEN, PI3KCA and EGFR genes) have been searched both in the tumor tissues and in the CTCs. HTERT was found mutated in CTCs of one patient’s tumor carrying mutant HTERT and wild type IDH1/2. We also included three IDH1 mutant glioma patients and one BRAFV600E mutant GBM patient in order to track these in CTCs. We did not find BRAF mutations in CTCs isolated from one recurrent BRAFV600E GBM patient with a very low allele frequency in the recurrent tumor (&amp;lt;1%). CONCLUSION We found CTCs in GBM patients newly diagnosed and at recurrence. Several factors may affect CTCs release such as tumor volume, CE and the CTCs genetic BACKGROUND , which seems to be heterogeneous. CTCs detection by our methodology could be helpful in the clinical setting for diagnostic, prognostic and theranostic purposes and for patients monitoring. Prospective study is ongoing in order to assess CTCs variations on and after therapy. This study, first investigated the genetic heterogeneity of CTCs released in the blood flow from the parental tumor.
OS07.6.A INVESTIGATING REGIONAL HETEROGENEITY AND PROGRESSION-ASSOCIATED MARKERS IN OLIGODENDROGLIOMAS
Authors: T O Millner, H Mikaeili, A Shabbir, A Lowe, S Brandner
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Oligodendrogliomas are defined by IDH-mutation, 1p/19q-codeletion and TERT promoter mutation. Molecular stratification of oligodendrogliomas has so far proved difficult, despite recent progress in other brain tumours. Loss of H3K27 trimethylation (H3K27me3) is seen in many, but not all oligodendrogliomas, and we have observed that this trimethylation mark is lost predominantly in low-grade oligodendrogliomas, and more often retained in high-grade tumours. The key aims of this project are to establish the downstream effects of H3K27me3 regulation in oligodendrogliomas to identify progression-associated biomarkers. MATERIAL AND METHODS 78 oligodendrogliomas (CNS WHO grade 2: n=38, and grade 3: n=40) were tested for H3K27me3 expression. These tumours showed either down-regulation (H3K27me3-), retention of expression (H3K27me3+) or intratumoural heterogeneity (H3K27me3Het). 65 regions across these three types were micro-dissected for DNA methylation profiling and RNA sequencing. RESULTS Of the H3K27me3- tumours 85% (35/41) were grade 2, of the H3K27me3+ tumours 100% (10/10) were grade 3, and of the H3K27me3Het tumours 87% (20/23) were grade 3. With DNA methylation arrays and derived copy number data we have shown a different breakpoint of the 1p chromosome in H3K27me3+ samples or areas, and in 15 paired samples, 6 gains and 12 losses in H3K27me3+ regions, and overall 24 copy number differences between H3K27me3+ and me3- areas within the same tumours, indicative of spatial genetic heterogeneity. RNA sequencing suggests distinct expression profiles between H3K27me3+ and H3K27me3- areas. CONCLUSION We have shown a close correlation between areas with high-grade features and H3K27me3 expression both between and within tumours. We have shown that H3K27me3+ and me3- areas within the same tumours show copy number changes and have differential gene expression. Using pathway analysis we have identified pathways and genes involved in tumour progression and mediation of histone modification. We are currently using these targets for functional studies and protein level validation with the overall aim of developing immunohistochemistry biomarkers.